The "first routine service flight in China's manned space programme" has entered its final countdown, with three astronauts, one of them a woman, preparing for lift-off today .

Wu Ping, deputy director of the programme's administrative office, said the nine previous Shenzhou space flights had been experimental and burdened with untested technology or equipment, such as life support and manual docking systems.

But the Shenzhou X mission, scheduled to blast off from the Jiuquan Satellite Launch Centre in Inner Mongolia at 5.38pm, would transport cargo and astronauts to the Tiangong 1 space module and bring them back within 15 days, similar to routine flights to the International Space Station (ISS), Wu said.

The end of experimental phase and the start of service flights meant China had acquired nearly all the essential technology and equipment to start construction of its space laboratory and space station next year .

A highlight of the Shenzhou X mission will be a lesson for primary and high school pupils taught by female astronaut Major Wang Yaping .

Wang, who will travel into space with Major General Nie Haisheng and Senior Colonel Zhang Xiaoguang , will be China's second female astronaut and its first teacher in space.

With live video and audio feeds, Zhang will conduct experiments to demonstrate principles of physics such as Newton's laws of motion .

Pupils will be allowed to ask questions and Wang, who has received a crash course on teaching primary students, will try her best to answer them.

"I will demonstrate to the pupils some magical physical phenomena in microgravity," she said yesterday. "In the vast expanse of space I will be a student as well."

China's space programme has long been criticised for its lack of transparency and the stern face it presents to ordinary people. But space authorities hope the space classes will kindle public interest and support for the national space endeavours.

The Shenzhou X astronauts will also play another unprecedented role - that of repairmen. During previous flights, some features of the orbiting Tiangong I module were found to be inconvenient for everyday working and living.

For instance the interior cladding was too soft and the hand grips awkwardly designed, posing some acrobatic challenges for crew as they sought to remain in one place or move to another. They will be replaced.

Some rubber seals ensuring air-tightness between the Tiangong I's capsules face a higher risk of leakage after nearly two years in operation and need replacement and some wires that also hindered astronauts will be replaced.

However, the maintenance work on Tiangong I will be of little lasting benefit. After the Shenzhou X crew leave, the space module will have completed its historic two-year mission and eventually plummet back to earth as discarded space junk, with half likely burn up in the atmosphere and rest likely to plunge into the ocean.

China' ambitious manned space programme includes building a twin-module space lab next year and a full-scale space station by 2020, the year the ISS retires. That would make China the only nation to run a human outpost in space.

But Chinese space authorities admit that they still lag far behind the United States and Russia.

Last month, Russia's Soyuz conducted a short rendezvous mission that took only six hours to reach the ISS, while Shenzhou X's approach to Tiangong I will take about two days.

This article appeared in the South China Morning Post print edition as First 'routine' mission set to go